Estimating quotients by rounding off dividend and divisor to the nearest ten

Estimating quotients by rounding off dividend and divisor

Group Activity 4

To find the estimate of 544 ÷ 32.

In pairs:

Round off 544 to the nearest ten.
Round off 32 to the nearest ten.
Divide the rounded off dividend by the rounded off divisor.
Discuss and share your results with other groups.

Example 5

By rounding off the numbers to the nearest ten, estimate 961 ÷ 31.

961 is 960 to the nearest tens.
31 is 30 to the nearest tens.

The estimate quotient is 32.

Exercise D

D1

In pairs, round off each of the following numbers to the nearest ten and work out.

2

3

4

Drag the answer from here to a column above

78 ÷23
24 ÷ 12
89 ÷26
59 ÷ 32

D2

Round off each number to the nearest ten and work out:

603 ÷ 26
715 ÷ 39
852 ÷ 46
724 ÷ 15

D3

Daudi put 837 litres of water into 35 litres containers. By rounding off the numbers to the nearest ten, work out the estimate.

837 is

to the nearest ten.

35 is

to the nearest ten.

The estimate quotient is

=

.

D4

A county government donated 175 water tanks. The tanks were shared equally among 25 welfare groups. By rounding off the numbers to the nearest ten, estimate the number of tanks each group received.

D5

A charitable organisation donated 864 packets of milk. The milk was packed in boxes each holding 24 packets. By rounding off the numbers to the nearest ten, estimate the number of boxes used.

864 is

to the nearest ten.

24 is

to the nearest ten.

The estimate quotient is

=

.

D6

Two hundred and thirty eight tourists were to be transported to an island using boats. Each boat would carry 17 people. By rounding off the numbers to the nearest ten, estimate the number of boats that were used.